多巴胺神经通路及其对蜜蜂行为的影响

蜜蜂复杂的社会行为受到了研究者的广泛关注,了解蜜蜂的学习、记忆、导航、信息传递等行为的神经分子基础,可对探索人类自身的脑科学和复杂社会行为的分子基础提供比较研究信息。本文综述了多巴胺的作用机制及其在蜜蜂行为中的作用,详细介绍了蜜蜂脑部的多巴胺受体,总结了蜜蜂脑部多巴胺水平的影响因子等,最后对进一步研究多巴胺神经通路对蜜蜂行为的作用及机制的前景做一展望。     

Small brains, bright minds

Learning, memory, and social behavior are innate properties of the honeybee that are essential for the survival of each individual as well as for the survival of the hive. The small, accessible brain of the honeybee and the availability of the complete sequence of its genome make this social insect an ideal model for studying the connection between learning, memory, and social behavior.     

农药对蜜蜂行为的影响

农药对蜜蜂的安全性评价包括在实验室以及更高层次的半大田和大田水平上的研究。蜜蜂行为是蜜蜂机体是否正常的直接表现,因此也是安全性评价的重要指标。文章概述农药对蜜蜂行为的影响,包括蜂王产卵行为,工蜂分工、采集行为、同群和外群工蜂辨别、学习行为和农药对蜜蜂的驱避性。     

Social learning of floral odours inside the honeybee hive

A honeybee hive serves as an information centre in which communication among bees allows the colony to exploit the most profitable resources in a continuously changing environment. The best-studied communication behaviour in this context is the waggle dance performed by returning foragers, which encodes information about the distance and direction to the food source. It has been suggested that another information cue, floral scents transferred within the hive, is also important for recruitment to food sources, as bee recruits are more strongly attracted to odours previously brought back by foragers in both honeybees and bumble-bees. These observations suggested that honeybees learn the odour from successful foragers before leaving the hive. However, this has never been shown directly and the mechanisms and properties of the learning process remain obscure. We tested the learning and memory of recruited bees in the laboratory using the proboscis extension response (PER) paradigm, and show that recruits indeed learn the nectar odours brought back by foragers by associative learning and retrieve this memory in the PER paradigm. The associative nature of this learning reveals that information was gained during mouth-to-mouth contacts among bees (trophallaxis). Results further suggest that the information is transferred to long-term memory. Associative learning of food odours in a social context may help recruits to find a particular food source faster.     

East learns from West: Asiatic honeybees can understand dance language of European honeybees

The honeybee waggle dance, through which foragers advertise the existence and location of a food source to their hive mates, is acknowledged as the only known form of symbolic communication in an invertebrate. However, the suggestion, that different species of honeybee might possess distinct 'dialects' of the waggle dance, remains controversial. Furthermore, it remains unclear whether different species of honeybee can learn from and communicate with each other. This study reports experiments using a mixed-species colony that is composed of the Asiatic bee Apis cerana cerana (Acc), and the European bee Apis mellifera ligustica (Aml). Using video recordings made at an observation hive, we first confirm that Acc and Aml have significantly different dance dialects, even when made to forage in identical environments. When reared in the same colony, these two species are able to communicate with each other: Acc foragers could decode the dances of Aml to successfully locate an indicated food source. We believe that this is the first report of successful symbolic communication between two honeybee species; our study hints at the possibility of social learning between the two honeybee species, and at the existence of a learning component in the honeybee dance language.     

Simulated Trust: A cheap social learning strategy

Animals use heuristic strategies to determine from which conspecifics to learn socially. This leads to directed social learning. Directed social learning protects them from copying non-adaptive information. So far, the strategies of animals, leading to directed social learning, are assumed to rely on (possibly indirect) inferences about the demonstrator’s success. As an alternative to this assumption, we propose a strategy that only uses self-established estimates of the pay-offs of behavior. We evaluate the strategy in a number of agent-based simulations. Critically, the strategy’s success is warranted by the inclusion of an incremental learning mechanism. Our findings point out new theoretical opportunities to regulate social learning for animals. More broadly, our simulations emphasize the need to include a realistic learning mechanism in game-theoretic studies of social learning strategies, and call for re-evaluation of previous findings.     

Memory impairment induced by cholinergic antagonists injected into the mushroom bodies of the honeybee

The role of honeybee central brain structures, suspected to be cholinergic, has been studied in learning and memory. The nicotinic antagonist mecamylamine and the muscarinic antagonist scopolamine were locally injected into the calyces and the alpha-lobes of mushroom bodies, and their effects on memory acquisition and retrieval were investigated using one-trial olfactory conditioning of the proboscis extension reflex. A strong impairment of the olfactory learning was noticed following mecamylamine injection into the mushroom body calyces. Mecamylamine and scopolamine disturbed retrieval processes when injected into the alpha-lobes of mushroom bodies but remain without effect on these processes when injected into the mushroom body calyces. These results emphasise the role of the cholinergic networks of the mushroom bodies in the formation and recall of memory in the honeybee. They suggest that the role of the brain structures in these processes is sequential. Mushroom body calyces involved in the associative process of olfactory learning could be relayed by the alpha-lobes for information retrieval.     

Conspecific and heterospecific information use in bumblebees

Heterospecific social learning has been understudied in comparison to interactions between members of the same species. However, the learning mechanisms behind such information use can allow animals to be flexible in the cues that are used. This raises the question of whether conspecific cues are inherently more influential than cues provided by heterospecifics, or whether animals can simply use any cue that predicts fitness enhancing conditions, including those provided by heterospecifics. To determine how freely social information travels across species boundaries, we trained bumblebees (Bombus terrestris) to learn to use cues provided by conspecifics and heterospecific honey bees (Apis mellifera) to locate valuable floral resources. We found that heterospecific demonstrators did not differ from conspecifics in the extent to which they guided observers'' choices, whereas various types of inorganic visual cues were consistently less effective than conspecifics. This was also true in a transfer test where bees were confronted with a novel flower type. However, in the transfer test, conspecifics were slightly more effective than heterospecific demonstrators. We then repeated the experiment with entirely naïve bees that had never foraged alongside conspecifics before. In this case, heterospecific demonstrators were equally efficient as conspecifics both in the initial learning task and the transfer test. Our findings demonstrate that social learning is not a unique process limited to conspecifics and that through associative learning, interspecifically sourced information can be just as valuable as that provided by conspecific individuals. Furthermore the results of this study highlight potential implications for understanding competition within natural pollinator communities.     

Effect of fipronil on side-specific antennal tactile learning in the honeybee

In the honeybee, the conditioning of the proboscis extension response using tactile antennal stimulations is well suited for studying the side-specificity of learning including the possible bilateral transfer of memory traces in the brain, and the role of inhibitory networks. A tactile stimulus was presented to one antenna in association with a sucrose reward to the proboscis. The other antenna was either not stimulated (A+/0 training), stimulated with a non-reinforced tactile stimulus B (A+/B− training) or stimulated with B reinforced with sucrose to the proboscis (A+/B+ training). Memory tests performed 3 and 24 h after training showed in all situations that a tactile stimulus learnt on one side was only retrieved ipsilaterally, indicating no bilateral transfer of information. In all these groups, we investigated the effect of the phenylpyrazole insecticide fipronil by applying a sublethal dose (0.5 ng/bee) on the thorax 15 min before training. This treatment decreased acquisition success and the subsequent memory performances were lowered but the distribution of responses to the tactile stimuli between sides was not affected. These results underline the role of the inhibitory networks targeted by fipronil on tactile learning and memory processes.     

Nest-mate recognition template of guard honeybees (Apis mellifera) is modified by wax comb transfer

In recognition, discriminators use sensory information to make decisions. For example, honeybee (Apis mellifera) entrance guards discriminate between nest-mates and intruders by comparing their odours with a template of the colony odour. Comb wax plays a major role in honeybee recognition. We measured the rejection rates of nest-mate and non-nest-mate worker bees by entrance guards before and after a unidirectional transfer of wax comb from a 'comb donor' hive to a 'comb receiver' hive. Our results showed a significant effect that occurred in one direction. Guards in the comb receiver hive became more accepting of non-nest-mates from the comb donor hive (rejection decreased from 70 to 47%); however, guards in the comb donor hive did not become more accepting of bees from the comb receiver hive. These data strongly support the hypothesis that the transfer of wax comb increases the acceptance of non-nest-mates not by changing the odour of the bees, but by changing the template used by guards.     

Social behavior and the evolution of neuropeptide genes: lessons from the honeybee genome

Honeybees display a fascinating social behavior. The structural basis for this behavior, which made the bee a model organism for the study of communication, learning and memory formation, is the tiny insect brain. Neurons of the brain communicate via messenger molecules. Among these molecules, neuropeptides represent the structurally most‐diverse group and occupy a high hierarchic position in the modulation of behavior. A recent analysis of the honeybee genome revealed a considerable number of predicted (200) and confirmed (100) neuropeptides in this insect. 1 Is this quantity merely the result of advanced mass spectrometric techniques and bioinformatic tools or does it reflect the expression of more of these important messenger molecules, more than known from other insects studied so far? Our analysis of the data suggests that the social behavior is by no means correlated with a specific increase in the number of neuropeptides. Indeed, the honeybee genome is likely to contain fewer neuropeptide genes, neuropeptide paralogues and neuropeptide receptor genes than the solitary fruitfly Drosophila. BioEssays 29:416–421, 2007. © 2007 Wiley Periodicals, Inc.     

Virus infection causes specific learning deficits in honeybee foragers

In both mammals and invertebrates, virus infections can impair a broad spectrum of physiological functions including learning and memory formation. In contrast to the knowledge on the conserved mechanisms underlying learning, the effects of virus infection on different aspects of learning are barely known. We use the honeybee (Apis mellifera), a well-established model system for studying learning, to investigate the impact of deformed wing virus (DWV) on learning. Injection of DWV into the haemolymph of forager leads to a RT-PCR detectable DWV signal after 3 days. The detailed behavioural analysis of DWV-infected honeybees shows an increased responsiveness to water and low sucrose concentrations, an impaired associative learning and memory formation, but intact non-associative learning like sensitization and habituation. This contradicts all present studies in non-infected bees, where increased sucrose responsiveness is linked to improved associative learning and to changes in non-associative learning. Thus, DWV seems to interfere with molecular mechanism of learning by yet unknown processes that may include viral effects on the immune system and on gene expression.     

Past Experiences Affect Interaction Patterns Among Foragers and Hive-Mates in Honeybees

Social insect colonies face the challenge of adjusting the behavior of individuals performing various tasks to a changing environment. It has been shown in several species that characteristics of interaction patterns between nestmates provide social information that allows individuals to adjust their behavior in adaptive ways. A well-studied example is the modulation of recruitment by dancing in honeybees ( Apis mellifera ) in response to the time, the foragers have to search for unloading partners and the number of unloading bees. Here we tested if experiences that hive bees acquired during past social interactions affect interactions with the incoming foragers. Bees returning with food containing a floral scent that was familiar to the hive bees from previous interactions had more food receivers during unloading and more followers during dancing displays compared with foragers returning with food containing a novel scent or unscented food. We also confirm that the number of receivers during food unloading is positively related to the motivation to dance immediately after unloading. Our results show that prior social experiences affect the ways in which individuals interact in the context of honeybee nectar collection and, therefore, how learning in hive bees contributes to the organization of this collective task.     

Everything is connected: Graph neural networks

In many ways, graphs are the main modality of data we receive from nature. This is due to the fact that most of the patterns we see, both in natural and artificial systems, are elegantly representable using the language of graph structures. Prominent examples include molecules (represented as graphs of atoms and bonds), social networks and transportation networks. This potential has already been seen by key scientific and industrial groups, with already-impacted application areas including traffic forecasting, drug discovery, social network analysis and recommender systems. Further, some of the most successful domains of application for machine learning in previous years—images, text and speech processing—can be seen as special cases of graph representation learning, and consequently there has been significant exchange of information between these areas. The main aim of this short survey is to enable the reader to assimilate the key concepts in the area, and position graph representation learning in a proper context with related fields.     

Task Partitioning in Insect Societies. II. Use of Queueing Delay Information in Recruitment

The collection and handling of colony resources such as food, water, and nest-construction material is often divided into subtasks in which the material is passed from one worker to another. This is known as task partitioning. If tasks are partitioned with direct transfer of material between foragers and receivers, queueing delays can occur as individuals search or wait for a transfer partner. Changes in environmental conditions and relative number of foragers and receivers affect these delays as well as colony ergonomic efficiency. These delays are used in recruitment in both honeybees and Polybia wasps. This study investigates the distribution of queueing delays and the information content and quality of those delays using a stochastic-simulation model. Information quality increases with colony size. When the relative proportions of foragers and receivers are suboptimal, the group in excess has better information. Individuals can increase information quality of delays by two mechanisms: averaging over consecutive trips and averaging over multiple transfers within a trip where direct transfer occurs. We suggest that multiple transfer occurs in the honeybee in order to improve information quality.     

Exploring the costs and benefits of social information use: an appraisal of current experimental evidence

Research on social learning has focused traditionally on whether animals possess the cognitive ability to learn novel motor patterns from tutors. More recently, social learning has included the use of others as sources of inadvertent social information. This type of social learning seems more taxonomically widespread and its use can more readily be approached as an economic decision. Social sampling information, however, can be tricky to use and calls for a more lucid appraisal of its costs. In this four-part review, we address these costs. Firstly, we address the possibility that only a fraction of group members are actually providing social information at any one time. Secondly, we review experimental research which shows that animals are circumspect about social information use. Thirdly, we consider the cases where social information can lead to incorrect decisions and finally, we review studies investigating the effect of social information quality. We address the possibility that using social information or not is not a binary decision and present results of a study showing that nutmeg mannikins combine both sources of information, a condition that can lead to the establishment of informational cascades. We discuss the importance of empirically investigating the economics of social information use.     

Long-term cultivation of in vitro <Emphasis Type="Italic">Apis mellifera</Emphasis> cells by gene transfer of human c-myc proto-oncogene

Establishment of cell lines representative of honeybee character would greatly assist in their analysis. Here, we show that immortalized cell line, designated as MYN9, has been generated from honeybee embryo by the gene transfer of human c-myc proto-oncogene. The morphology of the cell is characteristic of embryonic stem cell, although the cell is stable and does not spontaneously differentiate. Polymerase chain reaction analyses show that the cell is originated from authentic honeybee cell. It is proposed that the integration of human c-myc gene into honeybee precursor populations results in the establishment of stable cell line suitable for cellular and molecular studies.